use strict;
use warnings;
use IPC::Cmd qw( run );

my $tool = 'tar';
my $cmd = [ 'perl', '-e', 'warn "TEST FAILED IF YOU SEE THIS\n"' ];
my $buffer = '';
my @out = run( command => $cmd,
          buffer => \$buffer,
          verbose => 1 );
[download]

$ perl z.pl
Running [perl -e warn "TEST FAILED IF YOU SEE THIS\n"]...
TEST FAILED IF YOU SEE THIS
[download]

However, one simply has to remove verbose => 1 to make this a solution.